1. Field of the Invention
The present invention relates to an automobile suspension, and more particularly to a suspension having an actuator mechanism for adjusting wheel alignment including turning of a wheel.
2. Description of the Relevant Art
Conventional automobile suspensions include steering wheel suspensions as disclosed in Japanese Laid-Open Utility Model Publication No. 60/13860 and Japanese Laid-Open Patent Publication No. 60-128080, for example.
The suspension disclosed in the former publication primarily includes trailing arms, a lateral link, and a rear axle beam supported on a vehicle body by the trailing arms and the lateral link. The suspension further includes knuckles pivotally supported on respective opposite ends of the rear axle beam by means of kingpins, a relay rod extending parallel to and in front of the rear axle beam and operatively interconnecting the knuckle arms of the knuckles on the opposite ends of the rear axle beam, and a steering mechanism disposed parallel to and behind the rear axle beam and comprising a steering actuator and a steering link. The suspension doubles as a rear wheel steering apparatus. More specifically, by actuating the steering mechanism, one of the knuckle arms is angularly moved and the other knuckle arm is simultaneously angularly moved in parallel through the relay rod for turning rear wheels. According to this suspension, the lateral link and the steering link are of the same length and extend parallel to each other.
According to the suspension disclosed in the latter publication, a rear wheel steering system includes an input shaft extending longitudinally of a motor vehicle and having an eccentric shaft on the rear end of the input shaft, and a tubular member having a pinion on its front portion and an eccentric cam on its rear portion is rotatably fitted over the eccentric shaft. The pinion is held in mesh with an internal gear fixed to the vehicle body. A joint member interconnecting and supporting laterally spaced rear wheel tie rods is rotatably fitted over the eccentric cam.
The former suspension is however disadvantageous in that since the steering link and the relay rod are arranged parallel to the axle beam and the lateral link, these members result in an intricate structure, and affect the suspension geometry to the extent that it cannot be determined with large freedom.
The freedom of determining the suspension geometry is large with the latter suspension. However, in the latter suspension, the pinion of the tubular member is held in mesh with the internal gear fixed to the vehicle body, and the tie rods coupled to the knuckle arms are joined to the eccentric cam through joints. Where the suspension is employed to support rear wheels which are not steerable, therefore, not only the tie rods but also support members of the vehicle body have to be modified. The suspension cannot be used compatibly in both an automobile with only front wheels steerable and an automobile with front and rear wheels steerable.